Reproduction · Paper 1 — Free Biology HL Practice Questions

A fungal disease spreads rapidly through a wild strawberry population. Some plants reproduce asexually via stolons, producing genetically identical offspring; others reproduce sexually, producing seeds dispersed by animals. Which statement best explains why sexually reproducing plants are more likely to have some survivors after the disease outbreak?

A farmer grows a field of potato plants that are all clones of a single genotype. A new aphid species arrives and feeds on the leaves; nearly all plants die, but a few survive and produce small tubers. The farmer replants only tubers from the surviving plants the following season. What is the most likely outcome for the following season's crop?

Pollen grains of Lilium each contain cells with 12 chromosomes. During double fertilization, one sperm nucleus fuses with the egg cell and a second sperm nucleus fuses with the two polar nuclei to form the endosperm. What is the chromosome number in an endosperm cell?